The present invention refers to a device for transferring a foil matter from outside a machine to inside the machine, more particularly a machine using stamping foils for manufacturing packaging. A foil may be any material having the characteristics and capabilities herein described.
Such a machine is used for the embossing and the transfer by pressure of film portions, preferably of metal, coming from such foils onto a substrate of paper, plastic material, or more particularly cardboard. These operations are, for example, carried out in a machine equipped with a platen press processing plate-like elements, such as sheets of cardboard, for the foil stamping of given patterns. These patterns coming from a stamping foil are led between the travelling plane of the plate-like elements and the upper beam of the press. In an intermittent vertical movement, the movable lower platen will press the stamping foil against each cardboard sheet between printing plates and corresponding counterparts in order to deposit the metallic layer of the stamping foil in correspondence with the patterns of the printing plates. Once the transfer has been carried out, the lower platen lowers and the stamped cardboard sheet is withdrawn from the platen press so as to leave the space for a new sheet. In the same lapse of time, the stamping foil is moved so that a new blank sheet is placed in correspondence with the printing plates. The diecutting and transfer operation of the foil can then be repeated.
Such a machine can also be used for diecutting cardboard sheets in a succession of operations each carried out in an adjacent station. This succession of operations generally comprises the infeed of the sheet into the press, its diecutting by tools arranged on the platen, the stripping of waste by specific tools and the delivery in stacks of the diecut sheet elements. In order to optimize the possibilities of such a machine, it is known to convert it so that the initial diecutting station becomes a stamping station for stamping foils by replacing the tools of the stripping station by a device for loading and unwinding stamping foil reels. Such a conversion is illustrated by the machine described in patent EP 741,096.
The arrangement of a foil loading and unwinding device in the stripping station is described in detail in patent EP 741,096. This device in particular comprises a pair of parallel vertical arms between which are arranged crossbars that are used as supports for a plurality of stamping foil reels. The foil widths are typically of the order of 5 to 20 cm.
Due to the transverse arrangement of the rotation axes of the reels with respect to the longitudinal axis of the machine, the unwinding of the foils takes place parallel to the travelling direction of the sheets to stamp. Once the foil is used, its skeleton should be gathered either by rewinding or by dividing it in its length into a plurality of tapes which will then be shredded in order to reduce the space requirement. This operation is realized simultaneously and continuously outside of the machine, such as described in patent EP 739,721. The deviation of the foils or tapes is generally obtained by the arrangement of idling rollers arranged at 45° on their passage, so that they can turn around these rollers in order to be deviated outside the machine. However, the arrangement of a plurality of idling rollers causes adjustment and space requirement problems not facilitating the access. Effectively, when preparing the machine, each of these idling rollers should be positioned on the one hand laterally with respect to the machine frame so that each of them is located on the path of the corresponding foil and on the other hand angularly so that the deviation of this foil can be made accurately. These adjustments, however, are often tedious to realize, especially since there is a large number of idling rollers. Moreover, in such a case, access to each of these idling rollers is also more difficult for the engine operator who must arrange and adjust these rollers in a narrow environment loaded with various bulky mechanisms. Finally, once all these elements have been positioned and adjusted, there should be access to a passage for placing the beginning of each the foils liable to travel in the machine.
Although the majority of the metallic layers deposited on the packaging can be realized from narrow foils, generally not exceeding 30 cm, sometimes wider stamping foils have to be used, typically of the order of 50 to 70 cm, or a plurality of narrow foils arranged side by side, having a total width which approaches this magnitude.
However, the use of wide reels raises problems of handling in particular. Because of their weight, it is obviously impossible to move these reels by the physical strength of one man for positioning them in the machine. Thus, lifting means should be used, such as hoists or small vehicles able to easily move heavy loads. However, the positioning of such reels by these means makes handling in the machine delicate, and sometimes even impossible, either because of lack of space around the machine or due to impossible access inside a machine which is not intended for such means.
To solve this problem, it has been proposed to locate the device for supporting and loading reels in a module arranged outside the machine so as to enable or facilitate access to it. Advantageously, such an unwinding module is arranged perpendicular to the longitudinal axis of the machine, and facing the stripping station. The stripping station is transformed for the occasion into a space provided with idling rollers arranged at 45° with respect to this same axis. Coming from this unwinding module, the foil or foils enter perpendicularly into the machine through an open window in one of the side walls of its frame, and then the foils are deviated at a right angle and toward the longitudinal axis of the machine.
Operating satisfactory, this arrangement is limited by the maximum width of the foils which cannot exceed the width of the open window in the wall of the frame. However, for dimensional reasons, it is generally hardly possible to arrange a window exceeding 70 cm in the space released by the stripping station. Depending on the design of the machine, this limiting value is determined by the useful maximum length of the stripping station. Since this station comprises permanent mechanical means, which obviously already occupy a part of the available space and due to the fact that this station is sandwiched between the stamping or diecutting station upstream and the delivery station downstream, it is impossible to enlarge the inner space or to extend this stripping station when transforming the machine from a diecutting press into a stamping press.
A new problem then arises if the width of the stamping foils is larger than the possible maximum width of the window in the machine frame. Effectively, for very large foils, typically more than 70 cm and up to the useful maximum width of the machine, of the order of 1 meter or even more, it is impossible to introduce such foils into a machine as proposed in the prior art. This problem is not solved by the use of a plurality of foils arranged, for example side by side, the total width of which would be larger than the width of the window. Being thus aware that it is impossible to enlarge the window of passage of the foil through the wall of the machine, the problem to be solved by the skilled man is to find a solution for passing a foil of approximately 1 m width through a narrower window, for example of only 70 cm width.